Re: [PATCH] vfio: platform: use vfio_iommu_group_get/put

[Alex Williamson]

On Tue, 10 May 2016 15:40:28 +0800
Peng Fan <van.freenix@xxxxxxxxx> wrote:

> Hi Alex,
> 
> On Mon, May 09, 2016 at 09:32:38AM -0600, Alex Williamson wrote:
> >On Mon,  9 May 2016 18:01:43 +0800
> >Peng Fan <van.freenix@xxxxxxxxx> wrote:
> >  
> >> Use vfio_iommu_group_get and vfio_iommu_group_put, but not
> >> iommu_group_get or iommu_group_put.  
> >
> >I assume you're trying to duplicate the vfio_pci changes from commit
> >03a76b60f8ba to enable no-iommu mode.  That would be really relevant
> >information for the commit log.  
> 
> This is not to support non-iommu for vfio platform. I just think
> vfio_iommu_group_get/put is vfio core API and should be used by
> vfio-pci and vfio-platform.

Hi Peng,

I suppose I would consider this an optional part of the internal vfio
API, it's only real purpose it to provide the ability to create fake
groups which are only used for no-iommu.  It's perfectly legitimate to
use iommu_group_get/put if there is no desire to enable no-iommu.
Baptiste, Eric, do you have an opinion whether enabling no-iommu in
vfio/platform is something we should do?  Thanks,

Alex

> >> 
> >> Signed-off-by: Peng Fan <van.freenix@xxxxxxxxx>
> >> Cc: Baptiste Reynal <b.reynal@xxxxxxxxxxxxxxxxxxxxxx>
> >> Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
> >> ---
> >>  drivers/vfio/platform/vfio_platform_common.c | 6 +++---
> >>  1 file changed, 3 insertions(+), 3 deletions(-)
> >> 
> >> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> >> index e65b142..582885e 100644
> >> --- a/drivers/vfio/platform/vfio_platform_common.c
> >> +++ b/drivers/vfio/platform/vfio_platform_common.c
> >> @@ -561,7 +561,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
> >>  
> >>  	vdev->device = dev;
> >>  
> >> -	group = iommu_group_get(dev);
> >> +	group = vfio_iommu_group_get(dev);
> >>  	if (!group) {
> >>  		pr_err("VFIO: No IOMMU group for device %s\n", vdev->name);
> >>  		return -EINVAL;
> >> @@ -569,7 +569,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
> >>  
> >>  	ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev);
> >>  	if (ret) {
> >> -		iommu_group_put(group);
> >> +		vfio_iommu_group_put(group);
> >>  		return ret;
> >>  	}
> >>  
> >> @@ -589,7 +589,7 @@ struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
> >>  
> >>  	if (vdev) {
> >>  		vfio_platform_put_reset(vdev);
> >> -		iommu_group_put(dev->iommu_group);
> >> +		vfio_iommu_group_put(dev->iommu_group, dev);
> >>  	}
> >>  
> >>  	return vdev;  
> >